1. Field of the Invention
The present invention relates to improvements in anodeless riser assemblies for natural gas conduction and, more particularly, but not by way of limitation, it relates to an improved riser assembly wherein ful assembly, welding and coating of the metal portions of the riser pipe assembly can be carried out for subsequent positioning of plastic pipe components as connected to one or more distribution conduits.
2. Description of the Prior Art
The prior art includes numerous types of gas pipe riser assembly, i.e. a pipe connector for interconnection between the natural gas supply line and an above-ground gas meter. A U.S. Pat. No. 4,293,147 is of interest in that this patent teaches a secure metal-to-plastic coupling wherein a plastic pipe is inserted over a metal adaptor nipple having a series of ring and seal formations whereupon, subsequently, a sleeve member is forced down over the plastic to adaptor ring coupling thereby to bind the coupling in secure, gas-tight manner. This type of coupling, metal-to-plastic, has been particularly utilized in gas meter riser assemblies. Another form of prior riser assembly consists of a metal type nipple welded to a metal gas delivery tube which, in turn, is welded to a metal adaptor. The adaptor receives the plastic gas conduit thereover and is then seized by a suitable compression ring. This assembly is then disposed within a metal riser body which forms the necessary right angle bend for housing of the entire pipe assembly interconnecting the gas meter and the local distribution delivery pipes. This is an effective connection offering advantages of electrical isolation; however, a final weld must be made between the meter nipple and the riser body pipe after coating and this destroys the coating integrity of the riser assembly.